New Zealand captain Brendon McCullum has testified before the ICC's anti-corruption investigators but is not under investigation himself, according to New Zealand Cricket. The Daily Mail reported on Monday that it believed McCullum had told the ICC he had turned down offers of up to $180,000 to underperform in matches.

"New Zealand Cricket is dismayed that Brendon McCullum's testimony to the International Cricket Council has been leaked to the media," NZC said in a statement. "We can confirm that Brendon is not under investigation by the ICC and his testimony has actually been applauded by them. NZC has 100% confidence in our captain and his role in tackling corruption."

NZC's statement came after the Daily Mail carried parts of what it believed to be McCullum's statements to the ICC's anti-corruption investigators. According to the report, McCullum said he was first approached by a former player during the inaugural season of the IPL in 2008.

The former player allegedly explained the process of spread-betting to McCullum and is reported to have advised him to hide the money trail by buying property in Dubai, before claiming the money as profit from the sale of the property.

The paper also reported that it believed McCullum had divulged another approach by the player, this time during New Zealand's tour of England in 2008.

David White, the chief executive of NZC, said that while the ACSU was independent, it would ultimately be up to his governing body to decide what action to take once the investigation had concluded. "In regards to the investigation, what we had decided to do and agreed with the ICC was we would wait until their investigation was completed," he said. "Once they had all the information we would decide at New Zealand Cricket whether we would take any action.

"The protocols for the ICC are that the corruption unit is independent and the information is not shared with the member board. That's the approach, I've been in the role for just over two years and I found out just before Christmas [2013]. They act as an isolated unit and they keep information to themselves, and that is why we weren't informed earlier."

McCullum's testimony is part of the ICC's ongoing investigation into allegations of match-fixing and spot-fixing in cricket. In December last year, former New Zealand cricketer Lou Vincent confirmed that he was involved in an ICC anti-corruption investigation and in February, Vincent reported that he had been approached by an illegal bookmaker during the 2013 Bangladesh Premier League. Vincent is also believed to have told investigators of attempted fixing in England's Twenty20 Cup and CB40 competitions.

Heath Mills, the chief executive of the New Zealand players association, expressed his concern about the leaking of McCullum's testimony, particularly at a time when the future of the ACSU was under review. "To this point our players have had confidence in the ICC ACSU because of its independent structure and the experiences that players have had when dealing with its officers who operate with a high degree of integrity and professionalism," he said in a statement.

"Our understanding is that the player statements relating to the case in question have been provided to multiple parties, including several ICC member boards. We want to know why this has happened and what protections have been placed around the handling of these statements to ensure they remain confidential.

"We intend to ask these questions of the relevant authorities and hope other stakeholders will do the same. Particularly, now, as we have seen from media reports that there appears to be moves to change the operations of the ICC ACSU and its mandate. An effective fight against corruption both on, and importantly off the field, must be led by an independent unit that all stakeholders can have confidence in and is free of political interference.

"Corruption is the biggest issue facing sport. Whilst it is devastating to have these investigations occurring at the moment in New Zealand, we must recognise the problem and do our best to ensure it can be eliminated as best we can moving forward. To that end, a well-resourced and independent anti-corruption unit is essential."

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